// var num = 123  //new Number(123)
// num.a = 'aaa'
// //delete num.a 
// console.log(num.a);//undefined

var s='hello'
var n =123
//var n =new Number(123)
var f =true
var u =undefined
var o =null
var sy =Symbol('hello')
var b =123123123n 

console.log(typeof s);
console.log(typeof (n));
console.log(typeof (f));//boolean
console.log(typeof (u));//undefined
console.log(typeof (o));//object 这是一个bug
console.log(typeof (sy));//symbol
console.log(typeof (b));//bigint


var obj ={}
console.log(typeof(obj));
var date = new Date()
console.log(typeof(date));

 